Through the years a number of cameras have been developed for use in underwater photography. While the structural details and design aspects of such cameras have exhibited substantial variation, all generally include a camera body and lens and sealed environment. The sealed environment may comprise a separate sealed compartment within which the camera is supported and through which the lens has access to the underwater environment or, as is more common, the camera body itself and lens support may include integral seal mechanisms for protecting the interior of the camera. In addition, most underwater cameras are structured with reinforcement and additional strength to sustain the increased pressures found in operating underwater.
Perhaps one of the most popular types of underwater cameras used today comprises a thirty-five millimeter single lens reflex camera adapted for use underwater. One such camera is that presently manufactured by Nikon Corporation known under the brand name Nikonos. In basic features, the underwater thirty-five millimeter cameras very much resemble their above the water counterparts in that the camera body defines a generally rectangular elongated housing supporting a viewing aperture and having an internal prism for through the lens viewing. The lens generally extends forwardly through the front generally center portion of the camera body. Means are provided for winding and advancing the film as well as adjusting the focus and tripping the shutter. In the case of the underwater version of such cameras, the entire mechanism including all controls are sealed to protect the camera interior. The underwater thirty-five millimeter cameras generally used today also resemble their above the water counterparts in that they typically are limited to a maximum film size of thirty-six exposure film rolls.
Once the film within the underwater camera has been exposed, the camera must be returned to the surface to accomplish the reloading function. Once the camera is carefully dried, the back portion is removed to provide access to the film. The seal mechanism must be opened or broken to accomplish this access and as a result the seals must then be cleaned and their protective coatings (usually grease-type sealants). With the seals cleaned, serviced and relubricated, the camera is reloaded with fresh film and carefully reassembled to its sealed condition.
Because the reloading function of the underwater camera involves considerable effort and requires return trips to and from the surface for the diver, substantial limitations on the effectiveness of underwater photography operations is experienced due to the limited capacity of the underwater cameras. This wasted time is particularly critical in underwater photographic operations conducted in critical light conditions as are frequently found in underwater filming environments. To meet the problems and limitations imposed upon underwater photographic operations by limited film capacity of cameras, photographers typically load a plurality of cameras in one sitting above the surface and transport these multiple preloaded cameras down to the divers for their use. As each camera is exhausted, the diver simply switches to the next freshly loaded camera. While the use of multiple cameras provides some relief from the limitations imposed upon the operations by the limited capacity of underwater cameras, multiple camera use is expensive and cumbersome. In addition, the switching of cameras while more convenient than a trip to the surface, still imposes a substantial interruption for the diver in that the cameras must be interchanged and the focusing and various other settings of the camera must be redone with each new camera.
There remains, therefore, a need in the art for a system which increases the capacity of underwater cameras without imposing the burdens and expenses realized by use of multiple preloaded cameras.